Commit 0660b022 authored by Michał Kępień's avatar Michał Kępień
Browse files

Merge branch '2037-confidential-issue-v9_11' into 'security-v9_11'

[CVE-2020-8623]: Fix crash in pk11_numbits() with crafted packet when native-pkcs11 is used (v9.11)

See merge request isc-private/bind9!200
parents ae9af802 efe31ac2
5480. [security] When BIND 9 was compiled with native PKCS#11 support, it
was possible to trigger an assertion failure in code
determining the number of bits in the PKCS#11 RSA public
key with a specially crafted packet. (CVE-2020-8623)
[GL #2037]
5476. [security] It was possible to trigger an assertion failure when
verifying the response to a TSIG-signed request.
(CVE-2020-8622) [GL #2028]
......
......@@ -24,6 +24,18 @@
of Oracle for bringing this vulnerability to our attention. [GL #2028]
</para>
</listitem>
<listitem>
<para>
When BIND 9 was compiled with native PKCS#11 support, it was possible
to trigger an assertion failure in code determining the number of bits
in the PKCS#11 RSA public key with a specially crafted packet. This
was disclosed in CVE-2020-8623.
</para>
<para>
ISC would like to thank Lyu Chiy for bringing this vulnerability to
our attention. [GL #2037]
</para>
</listitem>
</itemizedlist>
</section>
......
......@@ -748,6 +748,7 @@ pkcs11dh_fromdns(dst_key_t *key, isc_buffer_t *data) {
CK_BYTE *prime = NULL, *base = NULL, *pub = NULL;
CK_ATTRIBUTE *attr;
int special = 0;
unsigned int bits;
isc_result_t result;
isc_buffer_remainingregion(data, &r);
......@@ -852,7 +853,11 @@ pkcs11dh_fromdns(dst_key_t *key, isc_buffer_t *data) {
pub = r.base;
isc_region_consume(&r, publen);
key->key_size = pk11_numbits(prime, plen_);
result = pk11_numbits(prime, plen_, &bits);
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
key->key_size = bits;
dh->repr = (CK_ATTRIBUTE *) isc_mem_get(key->mctx, sizeof(*attr) * 3);
if (dh->repr == NULL)
......@@ -1012,6 +1017,7 @@ pkcs11dh_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
dst_private_t priv;
isc_result_t ret;
int i;
unsigned int bits;
pk11_object_t *dh = NULL;
CK_ATTRIBUTE *attr;
isc_mem_t *mctx;
......@@ -1082,7 +1088,12 @@ pkcs11dh_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
attr = pk11_attribute_bytype(dh, CKA_PRIME);
INSIST(attr != NULL);
key->key_size = pk11_numbits(attr->pValue, attr->ulValueLen);
ret = pk11_numbits(attr->pValue, attr->ulValueLen, &bits);
if (ret != ISC_R_SUCCESS) {
goto err;
}
key->key_size = bits;
return (ISC_R_SUCCESS);
......
......@@ -983,6 +983,7 @@ pkcs11dsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
dst_private_t priv;
isc_result_t ret;
int i;
unsigned int bits;
pk11_object_t *dsa = NULL;
CK_ATTRIBUTE *attr;
isc_mem_t *mctx = key->mctx;
......@@ -1072,7 +1073,12 @@ pkcs11dsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
attr = pk11_attribute_bytype(dsa, CKA_PRIME);
INSIST(attr != NULL);
key->key_size = pk11_numbits(attr->pValue, attr->ulValueLen);
ret = pk11_numbits(attr->pValue, attr->ulValueLen, &bits);
if (ret != ISC_R_SUCCESS) {
goto err;
}
key->key_size = bits;
return (ISC_R_SUCCESS);
......
......@@ -332,6 +332,7 @@ pkcs11rsa_createctx_verify(dst_key_t *key, unsigned int maxbits,
key->key_alg == DST_ALG_RSASHA256 ||
key->key_alg == DST_ALG_RSASHA512);
#endif
REQUIRE(maxbits <= RSA_MAX_PUBEXP_BITS);
/*
* Reject incorrect RSA key lengths.
......@@ -376,6 +377,7 @@ pkcs11rsa_createctx_verify(dst_key_t *key, unsigned int maxbits,
for (attr = pk11_attribute_first(rsa);
attr != NULL;
attr = pk11_attribute_next(rsa, attr))
{
switch (attr->type) {
case CKA_MODULUS:
INSIST(keyTemplate[5].type == attr->type);
......@@ -396,12 +398,16 @@ pkcs11rsa_createctx_verify(dst_key_t *key, unsigned int maxbits,
memmove(keyTemplate[6].pValue, attr->pValue,
attr->ulValueLen);
keyTemplate[6].ulValueLen = attr->ulValueLen;
if (pk11_numbits(attr->pValue,
attr->ulValueLen) > maxbits &&
maxbits != 0)
unsigned int bits;
ret = pk11_numbits(attr->pValue, attr->ulValueLen,
&bits);
if (ret != ISC_R_SUCCESS ||
(bits > maxbits && maxbits != 0)) {
DST_RET(DST_R_VERIFYFAILURE);
}
break;
}
}
pk11_ctx->object = CK_INVALID_HANDLE;
pk11_ctx->ontoken = false;
PK11_RET(pkcs_C_CreateObject,
......@@ -1072,6 +1078,7 @@ pkcs11rsa_verify(dst_context_t *dctx, const isc_region_t *sig) {
keyTemplate[5].ulValueLen = attr->ulValueLen;
break;
case CKA_PUBLIC_EXPONENT:
unsigned int bits;
INSIST(keyTemplate[6].type == attr->type);
keyTemplate[6].pValue = isc_mem_get(dctx->mctx,
attr->ulValueLen);
......@@ -1080,10 +1087,12 @@ pkcs11rsa_verify(dst_context_t *dctx, const isc_region_t *sig) {
memmove(keyTemplate[6].pValue, attr->pValue,
attr->ulValueLen);
keyTemplate[6].ulValueLen = attr->ulValueLen;
if (pk11_numbits(attr->pValue,
attr->ulValueLen)
> RSA_MAX_PUBEXP_BITS)
ret = pk11_numbits(attr->pValue, attr->ulValueLen,
&bits);
if (ret != ISC_R_SUCCESS || bits > RSA_MAX_PUBEXP_BITS)
{
DST_RET(DST_R_VERIFYFAILURE);
}
break;
}
pk11_ctx->object = CK_INVALID_HANDLE;
......@@ -1461,6 +1470,8 @@ pkcs11rsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
CK_BYTE *exponent = NULL, *modulus = NULL;
CK_ATTRIBUTE *attr;
unsigned int length;
unsigned int bits;
isc_result_t ret = ISC_R_SUCCESS;
isc_buffer_remainingregion(data, &r);
if (r.length == 0)
......@@ -1478,9 +1489,7 @@ pkcs11rsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
if (e_bytes == 0) {
if (r.length < 2) {
isc_safe_memwipe(rsa, sizeof(*rsa));
isc_mem_put(key->mctx, rsa, sizeof(*rsa));
return (DST_R_INVALIDPUBLICKEY);
DST_RET(DST_R_INVALIDPUBLICKEY);
}
e_bytes = (*r.base) << 8;
isc_region_consume(&r, 1);
......@@ -1489,16 +1498,18 @@ pkcs11rsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
}
if (r.length < e_bytes) {
isc_safe_memwipe(rsa, sizeof(*rsa));
isc_mem_put(key->mctx, rsa, sizeof(*rsa));
return (DST_R_INVALIDPUBLICKEY);
DST_RET(DST_R_INVALIDPUBLICKEY);
}
exponent = r.base;
isc_region_consume(&r, e_bytes);
modulus = r.base;
mod_bytes = r.length;
key->key_size = pk11_numbits(modulus, mod_bytes);
ret = pk11_numbits(modulus, mod_bytes, &bits);
if (ret != ISC_R_SUCCESS) {
goto err;
}
key->key_size = bits;
isc_buffer_forward(data, length);
......@@ -1548,9 +1559,12 @@ pkcs11rsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
rsa->repr,
rsa->attrcnt * sizeof(*attr));
}
ret = ISC_R_NOMEMORY;
err:
isc_safe_memwipe(rsa, sizeof(*rsa));
isc_mem_put(key->mctx, rsa, sizeof(*rsa));
return (ISC_R_NOMEMORY);
return (ret);
}
static isc_result_t
......@@ -1729,6 +1743,7 @@ pkcs11rsa_fetch(dst_key_t *key, const char *engine, const char *label,
pk11_object_t *pubrsa;
pk11_context_t *pk11_ctx = NULL;
isc_result_t ret;
unsigned int bits;
if (label == NULL)
return (DST_R_NOENGINE);
......@@ -1815,7 +1830,11 @@ pkcs11rsa_fetch(dst_key_t *key, const char *engine, const char *label,
attr = pk11_attribute_bytype(rsa, CKA_MODULUS);
INSIST(attr != NULL);
key->key_size = pk11_numbits(attr->pValue, attr->ulValueLen);
ret = pk11_numbits(attr->pValue, attr->ulValueLen, &bits);
if (ret != ISC_R_SUCCESS) {
goto err;
}
key->key_size = bits;
return (ISC_R_SUCCESS);
......@@ -1901,6 +1920,7 @@ pkcs11rsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
CK_ATTRIBUTE *attr;
isc_mem_t *mctx = key->mctx;
const char *engine = NULL, *label = NULL;
unsigned int bits;
/* read private key file */
ret = dst__privstruct_parse(key, DST_ALG_RSA, lexer, mctx, &priv);
......@@ -2044,12 +2064,22 @@ pkcs11rsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
attr = pk11_attribute_bytype(rsa, CKA_MODULUS);
INSIST(attr != NULL);
key->key_size = pk11_numbits(attr->pValue, attr->ulValueLen);
ret = pk11_numbits(attr->pValue, attr->ulValueLen, &bits);
if (ret != ISC_R_SUCCESS) {
goto err;
}
key->key_size = bits;
attr = pk11_attribute_bytype(rsa, CKA_PUBLIC_EXPONENT);
INSIST(attr != NULL);
if (pk11_numbits(attr->pValue, attr->ulValueLen) > RSA_MAX_PUBEXP_BITS)
ret = pk11_numbits(attr->pValue, attr->ulValueLen, &bits);
if (ret != ISC_R_SUCCESS) {
goto err;
}
if (bits > RSA_MAX_PUBEXP_BITS) {
DST_RET(ISC_R_RANGE);
}
dst__privstruct_free(&priv, mctx);
isc_safe_memwipe(&priv, sizeof(priv));
......@@ -2084,6 +2114,7 @@ pkcs11rsa_fromlabel(dst_key_t *key, const char *engine, const char *label,
pk11_context_t *pk11_ctx = NULL;
isc_result_t ret;
unsigned int i;
unsigned int bits;
UNUSED(pin);
......@@ -2178,12 +2209,22 @@ pkcs11rsa_fromlabel(dst_key_t *key, const char *engine, const char *label,
attr = pk11_attribute_bytype(rsa, CKA_PUBLIC_EXPONENT);
INSIST(attr != NULL);
if (pk11_numbits(attr->pValue, attr->ulValueLen) > RSA_MAX_PUBEXP_BITS)
ret = pk11_numbits(attr->pValue, attr->ulValueLen, &bits);
if (ret != ISC_R_SUCCESS) {
goto err;
}
if (bits > RSA_MAX_PUBEXP_BITS) {
DST_RET(ISC_R_RANGE);
}
attr = pk11_attribute_bytype(rsa, CKA_MODULUS);
INSIST(attr != NULL);
key->key_size = pk11_numbits(attr->pValue, attr->ulValueLen);
ret = pk11_numbits(attr->pValue, attr->ulValueLen, &bits);
if (ret != ISC_R_SUCCESS) {
goto err;
}
key->key_size = bits;
pk11_return_session(pk11_ctx);
isc_safe_memwipe(pk11_ctx, sizeof(*pk11_ctx));
......
......@@ -25,7 +25,8 @@ void pk11_mem_put(void *ptr, size_t size);
CK_SLOT_ID pk11_get_best_token(pk11_optype_t optype);
unsigned int pk11_numbits(CK_BYTE_PTR data, unsigned int bytecnt);
isc_result_t
pk11_numbits(CK_BYTE_PTR data, unsigned int bytecnt, unsigned int *bits);
CK_ATTRIBUTE *pk11_attribute_first(const pk11_object_t *obj);
......
......@@ -962,13 +962,15 @@ pk11_get_best_token(pk11_optype_t optype) {
return (token->slotid);
}
unsigned int
pk11_numbits(CK_BYTE_PTR data, unsigned int bytecnt) {
isc_result_t
pk11_numbits(CK_BYTE_PTR data, unsigned int bytecnt, unsigned int *bits) {
unsigned int bitcnt, i;
CK_BYTE top;
if (bytecnt == 0)
return (0);
if (bytecnt == 0) {
*bits = 0;
return (ISC_R_SUCCESS);
}
bitcnt = bytecnt * 8;
for (i = 0; i < bytecnt; i++) {
top = data[i];
......@@ -976,26 +978,41 @@ pk11_numbits(CK_BYTE_PTR data, unsigned int bytecnt) {
bitcnt -= 8;
continue;
}
if (top & 0x80)
return (bitcnt);
if (top & 0x40)
return (bitcnt - 1);
if (top & 0x20)
return (bitcnt - 2);
if (top & 0x10)
return (bitcnt - 3);
if (top & 0x08)
return (bitcnt - 4);
if (top & 0x04)
return (bitcnt - 5);
if (top & 0x02)
return (bitcnt - 6);
if (top & 0x01)
return (bitcnt - 7);
if (top & 0x80) {
*bits = bitcnt;
return (ISC_R_SUCCESS);
}
if (top & 0x40) {
*bits = bitcnt - 1;
return (ISC_R_SUCCESS);
}
if (top & 0x20) {
*bits = bitcnt - 2;
return (ISC_R_SUCCESS);
}
if (top & 0x10) {
*bits = bitcnt - 3;
return (ISC_R_SUCCESS);
}
if (top & 0x08) {
*bits = bitcnt - 4;
return (ISC_R_SUCCESS);
}
if (top & 0x04) {
*bits = bitcnt - 5;
return (ISC_R_SUCCESS);
}
if (top & 0x02) {
*bits = bitcnt - 6;
return (ISC_R_SUCCESS);
}
if (top & 0x01) {
*bits = bitcnt - 7;
return (ISC_R_SUCCESS);
}
break;
}
INSIST(0);
ISC_UNREACHABLE();
return (ISC_R_RANGE);
}
CK_ATTRIBUTE *
......
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